[time-nuts] Flicker noise tutorial (free download)

[Mark Kahrs]

* Abstract:*
A deep understanding of how to reduce flicker phase noise (PN) in
oscillators is critical in supporting ultra-low PN frequency generation for
the advanced communications and other emerging high-speed applications.
Unfortunately, the current literature is either full of conflicting
theories and ambiguities or too complex in mathematics, hiding the physical
insights. In this brief, we comprehensively review the evolution of flicker
noise upconversion theories and clarify their controversial and confusing
parts. Two classes of such upconversion mechanisms in voltage-biased
LC-tank oscillators (nMOS-only and complementary) are specifically compared
and numerically verified using a commercial simulation model of 28-nm CMOS.
We identify that non-resistive terminations of both 2nd and 3rd harmonic
currents contribute to oscillation waveform asymmetries that lead to the
flicker noise upconversion. Further, we discuss three 1/f 3 PN reduction
mechanisms: waveform shaping, narrowing of conduction angle, and gate-drain
phase shift.
*Published in: *IEEE Transactions on Circuits and Systems II: Express Briefs
<https://ieeexplore.ieee.org/xpl/RecentIssue.jsp?punumber=8920> ( Volume: 68,
Issue: 2
<https://ieeexplore.ieee.org/xpl/tocresult.jsp?isnumber=9340029&punumber=8920>,
February 2021)

Download: https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=9286468